Effect of minocycline on healing of replanted dog teeth after extended dry times

Minocycline is available as a locally administered tetracycline derivative antibiotic (Arestin(TM), OraPharma, Inc., Warminster, PA, USA) which demonstrated antibacterial activity and anti-inflammatory action that may slow down resorptive processes after severe traumatic injuries to the dentition. A total of 48 premolar roots of six mongrel dogs were instrumented in an aseptic fashion with rotary nickel-titanium files and obturated with vertically condensed warm gutta percha. All accesses were sealed with glass ionomer, the roots extracted and then allowed to bench dry for 60 min. Group 1 consisted of 15 roots that were coated with minocycline and replanted and nine roots that were replanted without minocycline. Group 2 consisted of 24 roots, all of which were prepared with a uniform cemental defect down to sound dentin along the lateral aspect of the root, with a high-speed bur following the 60-min dry time. Half of the roots (12) were then coated with minocycline and replanted, and the other 12 roots were replanted without minocycline. After 4 months, the dogs were killed and the roots prepared for histological evaluation. About 5-mum thick cross-sections of the root and surrounding tissue taken every 90 mum were evaluated for healing. In addition, residual root mass was also measured in the roots of group 1 to determine the extent of root structure loss for each treatment method. The roots with and without minocycline treatment showed no significant differences between the remaining root mass or the percentage of favorably healed root surfaces. The use of minocycline is not currently recommended for prevention or attenuation of external root resorption following avulsion in a dog trauma model.